Lung volume changes during apnoeas in preterm infants

Vincent D Gaertner; Andreas D Waldmann; Peter G Davis; Dirk Bassler; Laila Springer; David Gerald Tingay; Christoph Martin Rüegger

doi:10.1136/archdischild-2022-324282

Lung volume changes during apnoeas in preterm infants

Arch Dis Child Fetal Neonatal Ed. 2023 Mar;108(2):170-175. doi: 10.1136/archdischild-2022-324282. Epub 2022 Aug 29.

Authors

Vincent D Gaertner¹, Andreas D Waldmann², Peter G Davis^{3

4

5}, Dirk Bassler⁶, Laila Springer⁷, David Gerald Tingay^{4

5

8}, Christoph Martin Rüegger⁶

Affiliations

¹ Newborn Research, Department of Neonatology, University Hospital and University of Zurich, Zurich, Switzerland vincent.gaertner@usz.ch.
² Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany.
³ Newborn Research Centre and Neonatal Services, The Royal Women's Hospital, Melbourne, Victoria, Australia.
⁴ The University of Melbourne, Melbourne, Victoria, Australia.
⁵ Murdoch Children's Research Institute, Melbourne, Victoria, Australia.
⁶ Newborn Research, Department of Neonatology, University Hospital and University of Zurich, Zurich, Switzerland.
⁷ Department of Neonatology, University Children's Hospital, Tübingen, Germany.
⁸ Department of Neonatology, The Royal Children's Hospital, Parkville, Victoria, Australia.

PMID: 36038255
DOI: 10.1136/archdischild-2022-324282

Abstract

Objective: Mechanisms of non-invasive high-frequency oscillatory ventilation (nHFOV) in preterm infants are unclear. We aimed to compare lung volume changes during apnoeas in preterm infants on nHFOV and nasal continuous positive airway pressure (nCPAP).

Methods: Analysis of electrical impedance tomography (EIT) data from a randomised crossover trial comparing nHFOV with nCPAP in preterm infants at 26-34 weeks postmenstrual age. EIT data were screened by two reviewers to identify apnoeas ≥10 s. End-expiratory lung impedance (EELI) and tidal volumes (V_T) were calculated before and after apnoeas. Oxygen saturation (SpO₂) and heart rate (HR) were extracted for 60 s after apnoeas.

Results: In 30 preterm infants, 213 apnoeas were identified. During apnoeas, oscillatory volumes were detectable during nHFOV. EELI decreased significantly during apnoeas (∆EELI nCPAP: -8.0 (-11.9 to -4.1) AU/kg, p<0.001; ∆EELI nHFOV: -3.4 (-6.5 to -0.3), p=0.03) but recovered over the first five breaths after apnoeas. Compared with before apnoeas, V_T was increased for the first breath after apnoeas during nCPAP (∆V_T: 7.5 (3.1 to 11.2) AU/kg, p=0.001). Falls in SpO₂ and HR after apnoeas were greater during nCPAP than nHFOV (mean difference (95% CI): SpO₂: 3.6% (2.7 to 4.6), p<0.001; HR: 15.9 bpm (13.4 to 18.5), p<0.001).

Conclusion: Apnoeas were characterised by a significant decrease in EELI which was regained over the first breaths after apnoeas, partly mediated by a larger V_T. Apnoeas were followed by a considerable drop in SpO₂ and HR, particularly during nCPAP, leading to longer episodes of hypoxemia during nCPAP. Transmitted oscillations during nHFOV may explain these benefits.

Trial registration number: ACTRN12616001516471.

Keywords: intensive care units, neonatal; neonatology; respiratory medicine.

Publication types

Randomized Controlled Trial

MeSH terms

Apnea*
Continuous Positive Airway Pressure / methods
Cross-Over Studies
Humans
Infant
Infant, Newborn
Infant, Premature*
Intermittent Positive-Pressure Ventilation / methods
Respiratory Distress Syndrome, Newborn*
Tidal Volume